British and Irish Lions assistant coach Graham Rowntree has been left to rue the loss of Paul O'Connell after injury effectively ended his career with the tourists.
O'Connell, who will be 37 when the Lions tour New Zealand in 2017, broke his arm during Saturday's thrilling first Test victory over Australia at Suncorp Stadium.
While he will not play again Down Under, missing the second and third Tests, towering Ireland lock O'Connell could stay on in a supporting role.
O'Connell attended Monday's final training session before the Lions tackle Melbourne Rebels on Tuesday and forwards specialist Rowntree admits the loss of the in-form lock is a blow for the tourists.
"He is one of the best, and he's in the form of his life as well," Rowntree said.
"He came into selection quite late because he had been out for so long with injuries during the season. Suddenly, he came back on the radar after that game (for Munster) against Harlequins in the European Cup. He was fit. In fact, I don't think he's ever been fitter.
"But you have got to get on with these things, which is why we brought so many players.
"Whether he is going to stay I am not sure yet. I would like him to because of the influence he has around the group. We will find out in the next four or five days what he is going to do.
"Losing someone like Paul galvanises a squad like us. We are a very tight group."
Asked if there was a case of siege mentality, Rowntree replied: "Yes".
While the Lions have already lost O'Connell, they are also awaiting further news on prop Alex Corbisiero, who is battling to overcome a calf muscle problem. It is uncertain at this stage whether or not he will be fit for the second Test on Saturday.
"We will know more in the next 24-48 hours," Rowntree said. "He played very well on Saturday. He stepped up to the challenge very well and was very accurate in everything he did.
"It (losing Corbisiero) would be a big blow, but it would be another test for the strength in depth that we've got in the squad. So far, that strength in depth hasn't let us down."
Rowntree added: "We are very mindful of training volumes. I can only attribute it (Lions injuries) to the intensity of the opposition.
"We've been very accurate with our training. We have a lot of GPS data and heart-rate data. We very much train in short, intense sessions, so it's not from over-training.
"Such is the feeling and culture we have within the group, it will definitely bring us together. 'Gats' (head coach Warren Gatland) spoke to the lads three times today about this weekend, how we've got to lift another couple of gears.
"I thought we deserved that victory last weekend, but our intensity and accuracy have to go up another couple of gears, and I'm pretty confident we can do that."